From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Investigation report into the cause of carburetter flooding on a 20/25 HP model.
| Identifier | ExFiles\Box 107\1\ scan0320 | |
| Date | 8th June 1935 | |
| To Sg.{Arthur F. Sidgreaves - MD} A Wor.{Arthur Wormald - General Works Manager} c. to C. c. to E.{Mr Elliott - Chief Engineer} c. to Dy.{F R Danby} c. to Mx.{John H Maddocks - Chief Proving Officer} 20/25 HP. Carburetter Flooding. An examination of Sg{Arthur F. Sidgreaves - MD}'s car, which was available for our inspection at Lillie Hall in a flooding condition, indicated that the float chamber mechanism was working satisfactorily and that therefore the flooding was due to foreign matter on the needle valve seat. Since then we have demonstrated that foreign matter inserted in the flexible pipe will pass through on to the needle valve seat and cause copious flooding. Until we were able to demonstrate this we did not think that dirt could produce such violent flooding, and were looking for some other trouble. The question arises, how can dirt get to the carburetter in view of the efficient plate filter which we fit. Examination has shown that quite a large quantity of foreign matter exists in some of the flexible tubes on the carburetter side of the filter. The tube being corrugated, this lies in the bottom of the corrugations and is difficult to dislodge by ordinary washing. As far as our investigations have gone, therefore, we are satisfied so far that - (a) Foreign matter on the needle valve seat can cause the trouble complained of. (b) Such foreign matter can get on to the seat owing to its being originally located in the flexible pipe. This confirms our experience on the SpectreCodename for Phantom III, where until we got the system clean on the carburetter side of the filter, we had continual trouble with flooding, but afterwards this trouble completely disappeared. | ||